/*
 * jPOS Project [http://jpos.org]
 * Copyright (C) 2000-2015 Alejandro P. Revilla
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package org.jpos.iso;

import java.io.IOException;
import java.io.InputStream;
import java.util.BitSet;

/**
 * ISOFieldPackager Binary Bitmap
 *
 * @author apr@cs.com.uy
 * @version $Id$
 * @see ISOComponent
 * @see ISOBitMapPackager
 */
public class IFB_BITMAP extends ISOBitMapPackager {
	public IFB_BITMAP() {
		super();
	}

	/**
	 * @param len         - field len
	 * @param description symbolic descrption
	 */
	public IFB_BITMAP(int len, String description) {
		super(len, description);
	}

	/**
	 * @param c - a component
	 * @return packed component
	 * @throws ISOException
	 */
	public byte[] pack(ISOComponent c) throws ISOException {
		BitSet b = (BitSet) c.getValue();
		int len =
				getLength() >= 8 ?
						b.length() + 62 >> 6 << 3 : getLength();
		return ISOUtil.bitSet2byte(b, len);
	}

	/**
	 * @param c      - the Component to unpack
	 * @param b      - binary image
	 * @param offset - starting offset within the binary image
	 * @return consumed bytes
	 * @throws ISOException
	 */
	public int unpack(ISOComponent c, byte[] b, int offset)
			throws ISOException {
		int len;
		BitSet bmap = ISOUtil.byte2BitSet(b, offset, getLength() << 3);
		c.setValue(bmap);
		len = bmap.get(1) ? 128 : 64;
		if (getLength() > 16 && bmap.get(65))
			len = 192;
		return Math.min(getLength(), len >> 3);
	}

	public void unpack(ISOComponent c, InputStream in)
			throws IOException, ISOException {
		BitSet bmap = ISOUtil.byte2BitSet(new BitSet(64), readBytes(in, 8), 0);
		if (getLength() > 8 && bmap.get(1)) {
			ISOUtil.byte2BitSet(bmap, readBytes(in, 8), 64);
		}
		if (getLength() > 16 && bmap.get(65)) {
			ISOUtil.byte2BitSet(bmap, readBytes(in, 8), 128);
		}
		c.setValue(bmap);
	}

	public int getMaxPackedLength() {
		return getLength() >> 3;
	}
}
